I was one of the few that lambasted Intermountain Railway Co for the problems associated with their F7 release with the improperly molded B units. I recently received the Southern Pacific "Black Widow" version of the F7 (both A & B units). The correction to the B unit was done and the ABA set I got is running great. In fact... I got engines from two other manufacturers (Kato & Atlas) together with the IMRC F7s... and the IMRC models are better runners. The IMRC units are running quietly and smoothly and all three are fairly close in speed. The Kato F3 A/B/B units have the typical Kato low 'whirrng sound' when running and do not have the slow speed control that the IMRC units have. I was somewhat disappointed with the Atlas GP40s. The three units were all somewhat different in speed... one even stalls every so often on straight KATO track... all are noisier than the Kato 'whirring'. I'm guessing... hoping... that running the Atlas models will eventually improve them. I would have to say... that as of this current batch of items.. IMRC has redeemed some confidence from me.
